Micro robot

ABSTRACT

A micro robot having a size of about 1 cm 3  and capable of wireless control. This robot includes at least two sensors (12, 14) having detection regions thereof overlapping partially with each other, at least a pair of independently operated driving units (30, 28) having driving points spaced apart in a direction perpendicular to a moving direction, control units (40, 58, 60, 62) for controlling the driving units on the basis of the outputs of the sensors, and a rechargeable power supply portion (16) for supplying a power supply voltage to the sensors, the driving units and the control units. The control units and the power supply units are disposed between the driving units.

TECHNICAL FIELD

The present invention relates relates to a micro robot which has a verysmall size of, for example, about one cubic centimeter and which can becontrolled in a wireless manner.

BACKGROUND TECHNIQUE

In the case of controlling a robot in a wireless manner, conventionally,control called radio control was carried out and a control system usingan electric wave was used. In order to perform direction control,steering was made in accordance with a control signal superimposed on anelectric wave. Further, in order to make a robot autonomously proceed ina desired direction, a directional antenna was used or a visual sensoror the like was used together. Wheels were used in a running portion tothereby reduce running resistance. Further, terminals for changing wereconstituted by rigid contacts and formed in an recess portion of a body.

However, such a robot control system as mentioned above is not suitablefor minimization because numbers of electric elements were required in atransmission side as well as in a reception side because of using anelectric wave, and a steering mechanism was further required. Further,in order to constitute the system adapted to make a robot autonomouslymove toward a direction from which an electric wave was transmitted, itwas necessary to additionally provide such an antenna or sensor asmentioned above, and the control system was therefore not suitable forminimization also in this point. Furthermore, in the case where partother than a driving portion was supported by wheels, the robot couldnot go over a large uneven portion when the wheels were small, whileminimization was difficult when the wheels were large. The chargingterminals could not be made small in view of handling, and they were anobstacle to minimization.

Further, even if it was intended to make such a robot operate any work,the situation were such that there is no any mechanism suitabletherefor.

Further, it was impossible to mount a battery of a large capacitybecause of a demand for minimization, and although it was desirable toperform contactlessly charging in view of wireless control, thesituation was that such a charging mechanism was not yet developed.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a micro robot havinga size of about one cubic centimeter.

It is another object of the present invention to provide a micro robotin which a work mechanism is provided in a robot body having a size ofabout one cubic centimeter.

It is a further object of the present invention to provide a micro robotwhich has a size of about one cubic centimeter and which is chargeablecontactlessly.

According to an aspect of the present invention, a micro robotcomprises: at least two sensors having respective detection regionspartly overlapping each other; at least one pair of driving means beingdriven independently of each other and having driven points separatedfrom each other in the direction perpendicular to a direction ofmovement; a control portion for controlling the driving means on thebasis of outputs of the sensors; and a chargeable power source portionfor supplying a power source voltage to the sensors, the driving meansand the control portion, the control portion and the power sourceportion being arranged between the driving means. By such aconfiguration, it is made possible to achieve minimization. Particularlyby the fact that the respective detection regions of the sensors areoverlapped each other, it is possible to obtain a function that therobot can be moved autonomously toward a target by means of a simplecircuit. Further, since the driving means are controlled independentlyof each other, complicated operation can be controlled by means of asimple mechanism. Furthermore, since the control portion and the powersource portion are arranged between the pair of driving means, the robotbody can be minimized.

According to another aspect of the present invention, the micro robot issupported by three points including the two driven points which aredriven relative to a running ground by the pair of driving means, andone sliding point which slidably contacts with the running ground.Accordingly, balanced and stable running can be carried out.

According to a further aspect of the present invention, in the microrobot, a line segment connecting the two driven points interlinks withthe direction of gravity of the micro robot at its center of gravitydepending on inclination of the running ground, and the position of thesliding point varies between the front and back of the interlinkage. Thesliding point varies depending on the positional relation between theline segment connecting the driven points and the center of gravity, andon an upward slope, therefore, the center of gravity of the robot takesa position upper than the driven points so that the frictional forcebecomes large to thereby improve the climbing force.

According to a still further aspect of the present invention, the microrobot further comprises a flexible protrusion which projects from a bodyand which is conductive with the power source portion. Not only theprotrusion portion functions as a sliding portion so that the runningresistance is reduced to improve the running property as well as theproperty of running covering the whole distance, but also the protrusionportion is made to be electrically conductive with the power sourceportion so as to function as a charging terminal so that the chargingwork has become easy and such a risk of damaging the power sourceportion due to concentration of stress has been prevented fromoccurring.

According to an0ther aspect of the present invention, in the microrobot, each of the driving means includes a motor constituted by astepping motor, so that the quantity of movement can be programmed withthe number of steps.

According to a further aspect of the present invention, in the microrobot, the control portion carries out accelerating control on thedriving means at the time of starting driving of the driving means, andwherein the control portion makes the driving condition of one of thedriving means coincide with that of the other driving means when thedriving of the one driving means is started while the other drivingmeans is being driven. Thus, the mode of movement can smoothly shiftedfrom turning movement to straight movement.

According to a still further aspect of the present invention, the microrobot further comprises an obstacle sensor for detecting an obstacle sothat when the obstacle sensor detects an obstacle the control portionreversely drives at least one of the driving means for a predeterminedperiod of time and then returns the at least one driving means to itsnormal operation. Thus, it is possible to make the micro robotautomatically move in the direction to go away far from the obstacle.

According to another aspect of the present invention, in the microrobot, the control portion detects presence or absence of rotation of amotor included in each of the driving means on the basis of an inducedvoltage in a winding of the motor. For example, if the fact that themotor is not rotating is detected, all the motors are driven toreversely rotate for a predetermined period of time, the motor which wasdetected so that it did not rotate is then drive for a predeterminedperiod of time, and thereafter the normal operation is carried out sothat the micro robot can be made to automatically move in the directionaway far from the obstacle.

According to a further aspect of the present invention, in the microrobot, the control portion drives the driving means while accelerating,and wherein the control portion performs driving with driving pulses thewidth of which is widened at the time of starting while narrowed at thetime of high speed. Accordingly, large driving force can be obtained,and the energy efficiency is so improved that the consumption of thepower source portion is reduced.

According to a still further aspect of the present invention, in themicro robot, the control portion makes the respective timings ofsupplying driving pulses to the driving means coincident with eachother. In this case the property of straight running is improved.

According to another aspect of the present invention, the micro robotfurther comprises at least two screws driven by the driving means, andwherein the control portion makes the respective timings of supplyingdriving pulses to the driving means shift from each other. Therespective timings of sending out driving pulses are shifted so that therapid consumption of the power source is prevented from occurring.

According to a further aspect of the present invention, a micro robotcomprises: at least two direction control sensors having respectivedetection regions partly overlapping each other; at least one pair ofdriving means being driven independently of each other and having drivenpoints separated from each other in the direction perpendicular to adirection of movement; a work control sensor which receives a workinstruction contactlessly from an operation side; a work driving means;and a control portion for controlling the driving means on the basis ofoutputs of the direction control sensors and for controlling the workdriving means on the basis of an output of the work control sensor. Thetraveling direction is automatically controlled on the basis of anoutput of the direction control sensor, and after the robot has beenmoved to a desired position, an instruction is given from the operationside to the work control sensor to thereby drive the work driving meansso that a desired work is carried out.

According to a still further aspect of the present invention, a microrobot comprises; a reception sensor for contactlessly receiving anexternal instruction; at least one pair of driving means being drivenindependently of each other and having driven points separated from eachother in the direction perpendicular to a direction of movement; a workdriving means; and a control portion for driving the driving means andfor controlling the work driving means, on the basis of an output of thereception sensor. This micro robot is provided with no direction controlsensor but the function of the direction control sensor is given to thereception sensor. Accordingly, the traveling direction can be controlledand work can be carried out on the basis of an external instructionthrough the reception sensor.

According to another aspect of the present invention, the micro robotfurther comprises a signal transmission element for externally andcontactlessly transmitting a signal and a detection element; and whereinthe control means causes the signal transmission element to transmitinformation detected by the detection element. Thus, the situation ofthe robot is informed to the outside.

According to a further aspect of the present invention, in the microrobot, the work driving means includes a micro pump which is driven todischarge a fluid bit by bit.

According to a still further aspect of the present invention, in themicro robot, the work driving means includes a hand mechanism and adriving means for driving the hand mechanism. By this hand mechanism, itis made possible to carry out handling such as conveying parts or thelike.

According to another aspect of the present invention, a micro robot isattached to an end portion of an endoscope, and comprises: aphotovoltaic element for receiving light through optical fibers and forsupplying a power source voltage; a micro pump for discharging a fluid;and a control portion for analyzing a control signal superimposed on thelight obtained through the optical fibers to thereby drive the micropump. By means of the endoscope, it is possible that while the inside ofbody is being inspecting, the micro pump is driven at a desired positionto thereby discharge, for example, a medical fluid.

According to a further aspect of the present invention, a micro robotcomprises: a robot body provided with a built-in motor and disposedwithin a non-magnetic pipe containing a fluid therein; and an excitingdevice provided at the outside of the non-magnetic pipe and forsupplying a stator of the motor with magnetic flux corresponding to thenumber of poles of the motor. Thus, driving energy can be suppliedcontactlessly from the outside and the driving of the motors can becontrolled.

According to a still further aspect of the present invention, in themicro robot, the exciting device is supported so as to be movable in thedirection of length of the nonmagnetic pipe. With the movement of theexcitation device, the robot body moves so that the position control ofthe robot body can be carried out.

According to another aspect of the present invention, a micro robotcomprises: at least two sensors having respective detection regionspartly overlapping each other; at least one pair of driving means beingdriven independently of each other and having driven points separatedfrom each other in the direction perpendicular to a direction ofmovement; a control portion for controlling the driving means on thebasis of outputs of the sensors; and a contactlessly chargeable powersource portion for supplying a power source voltage to the sensors, thedriving means and the control portion. Since the detection regions areoverlapped each other, a function of autonomous movement toward a targetcan be realized with a simple circuit. Further, since the driving meansare controlled independently of each other, complicated operation can becontrolled by means of a simple mechanism to thereby make it possible tominimize the micro robot body. Further, since the power source portionis made chargeable contactlessly, perfect wireless control can be made.

According to a further aspect of the present invention, in the microrobot, each of the driving means includes a built-in motor so that aninduced voltage is generated in a winding of the motor by a magneticfield of an externally provided charging coil, the induced voltage beingused after rectified to charge the power source. The micro robot furthercomprises a mechanism by which the micro robot automatically movestoward a stand in which the charging coil is provided. Accordingly, ifthe voltage of the power source portion becomes low, the robot movesautomatically toward the charging stand so that the power source portionis automatically charged.

According to a still further aspect of the present invention, in themicro robot, a photovoltaic element or a thermoelectric generationelement is connected to the power source portion so that thephotovoltaic element or the thermoelectric generation element generateselectricity in response to light or in response to heatabsorption/generation of an externally provided heatabsorption/generation body to thereby charge the power source portion.Thus, the power source portion is charged automatically.

Further, a booster circuit is connected to the power source portion sothat the booster circuit performs automatic boosting operation inaccordance with a voltage of the power source portion. Thus, the circuitcan be made to operate normally even if the voltage of the power sourceportion becomes low.

According to another aspect of the present invention, a micro robotcomprises: a driving means having a built-in motor for driving a fin torotate; an arm adapted to open outward so as to engage with a pipe innerwall; a contactlessly chargeable power source portion for supplying apower source voltage to the sensor, the driving means and the controlportion; and a control portion which stops the driving of the motor andopens the arm so as to stop within a fluid, when the voltage of thepower source portion becomes a value not higher than a predeterminedreference voltage value. When the fin is rotated by a flow of the fluidduring stoppage, an induced voltage is generated in a winding of themotor so that the power source portion is charged by the induced voltageafter rectified. Accordingly, the charging can be made automaticallyinside a fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an embodiment of the micro robot according tothe present invention.

FIG. 2 is a top view of FIG. 1.

FIG. 3 is a bottom view of FIG. 1.

FIG. 4 is an explanatory view in the case where the robot body goes upon the inclined running ground.

FIG. 5 is a side view of another embodiment of the micro robot accordingto the present invention.

FIG. 6 is a bottom view of FIG. 5.

FIG. 7 is an enlarged side view of a wheel of the above-mentioned microrobot.

FIG. 8 is a block diagram showing in detail the circuit portion.

FIG. 9 is a circuit diagram of the sensor.

FIG. 10 is a plan view of the driving portion.

FIG. 11 is a development view of the driving portion of FIG. 10.

FIGS. 12 A-12G illustrate a timing chart showing the basic operation ofthe robot of the embodiment of FIG. 1 or FIG. 5.

FIG. 13 is a timing chart showing the basic operation of the robot ofthe embodiment of FIG. 5 at the time of starting the driving.

FIG. 14 is a timing chart showing the operation of the robot of theembodiment of FIG. 5 at the time of starting the driving.

FIGS. 15 A-15D illustrate a waveform diagram of the driving pulses ofthe robot of the embodiment of FIG. 5.

FIG. 16 is a flowchart showing the processing (No. 1) in the case ofavoiding an obstacle.

FIG. 17 is an explanatory view of the above avoiding operation.

FIG. 18 is a flowchart showing the processing (No. 2) in the case ofavoiding an obstacle.

FIG. 19 is an explanatory view of the above avoiding operation.

FIG. 20 A and 20B illustrate a timing chart showing a method ofdetecting presence or absence of the rotation of the stepping motor.

FIGS. 21, 22 and 23 are a front view, a side view and a back view of anembodiment of the micro robot according to the present invention.

FIG. 24 is a block diagram showing the peripheral circuits of the motordriving circuit of the embodiment of FIG. 21 through 23.

FIG. 25 is a top view of a further embodiment of the micro robotaccording to the present invention.

FIG. 26 is a block diagram showing in detail the circuit portion of theembodiment of FIG. 25.

FIG. 27 is a flowchart showing the control operation of the circuitportion of FIG. 26.

FIG. 28 is a flowchart showing the operation in the case where the workcontrol sensor is not provided in FIG. 25 and 26.

FIG. 29 is a block diagram showing in detail another embodiment of thecircuit portion.

FIG. 30 is a top view of the robot body of another embodiment of thepresent invention.

FIG. 31 is a flowchart showing the control operation of the circuitportion of FIG. 29.

FIG. 32 is a sectional view showing an example in which the micro robotaccording to the present invention is applied to an endoscope.

FIG. 33 is a bottom view of a further embodiment of the micro robotaccording to the present invention.

FIG. 34 is a side view of the micro robot of FIG. 33.

FIG. 35 is a side view of another embodiment of the micro robotaccording to the present invention.

FIG. 36 is a bottom view of the micro robot of FIG. 35.

FIG. 37 is a block diagram showing in detail the circuit portion of themicro robot of FIGS. 35 and 36.

FIG. 38 is a flowchart showing the control operation of the micro robotof FIGS. 35 through 37.

FIG. 39 is a view showing the state in which the micro robot of FIG. 35has raised its hand.

FIG. 40 is a view showing the state in which the micro robot of FIG. 35has opened its hand.

FIG. 41 is a conceptual view of a further embodiment of the micro robotaccording to the present invention.

FIG. 42 is a side view of FIG. 41.

FIG. 43 is a view showing in detail the work motor.

FIGS. 44, 45 and 46 are views showing principle of operation of the workmotor.

FIG. 47 is a block diagram showing in detail the circuit portion inwhich a mechanism for performing charging by electromagnetic induction.

FIG. 48 is a block diagram showing in detail the motor driving circuitof the embodiment of FIG. 47.

FIG. 49 is a diagram showing discharge characteristic of an electricdouble layer capacitor constituting the power source portion.

FIG. 50 is a circuit explanatory view showing in detain a voltageregulator.

FIGS. 51A and 51B illustrate the boosting circuitry for performing a 1.5times charge boosting operation.

FIGS. 52A and 52B illustrate the boosting circuitry for performing acharge boosting operation of 2.0.

FIGS. 53A and 53B illustrate the boosting circuitry for performing a 3.0charge boosting operation. therefor.

FIG. 54 is a perspective view of a charge stand.

FIG. 55 is a block diagram showing the configuration of an energy supplydevice.

FIG. 56 is a flowchart showing the operation at the time of automaticcharging.

FIG. 57 is a front view of another embodiment of the micro robotaccording to the present invention.

FIG. 58 is a back view of FIG. 57.

FIG. 59 is a sectional view along 59--59 in FIG. 58.

FIG. 60 is a view for explaining the function of the arm of FIG. 57.

FIG. 61 is a block diagram showing the configuration of the controlportion in the case where charging is made by means of a photovoltaicelement.

FIG. 62 is a flowchart showing the operation of the embodiment of FIG.61.

FIG. 63 is a flowchart showing the operation in the case of control incombination of charging, avoiding obstacles, working, and returning tothe base portion.

THE BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a side view showing a micro robot according to an embodimentof the present invention, and FIG. 2 is a top plan view thereof. A pairof sensors 12 and 14 are provided at front portions of a robot body 10as shown in the drawings. Although a light sensor constituted, forexample, by a photodiode, a phototransistor, or the like, an ultrasonicsensor for converting an acoustic wave into a voltage with apiezo-electric element, or the like is used as each of the sensors 12and 14, a phototransistor is used in this embodiment. The sensors 12 and14 have fields of view A1 and A2 as their detection regionsrespectively. Since the fields of view A1 and A2 overlap each other atthe center portion, the sensors 12 and 14 have an overlapped field ofview A3. Therefore, when light from a light source exists in front, thatis, in the field of view A3, the sensors 12 and 14 detect the light.Being disposed in a left side portion of the robot body 10, the sensor12 is stated as an L-sensor in a flowchart of the drawing which will bedescribed later. Similarly to this, being disposed in a right sideportion in the robot body 10, the sensor 14 is stated as an R-sensor.

FIG. 3 is a bottom plan view of FIG. 1. A power source portion 16configured as a thin plate, is located at a central portion and isconstituted, for example, by an electric double layer capacitor, a Ni-Cdbattery, and the like. A circuit portion 22 configured as a thin plateis provided in the close vicinity of the power source portion 16. Thecircuit portion 22 includes a CMOS-IC 24, a pull-down chip resistor 26,and the like, mounted on a circuit substrate 23, the detail thereofbeing described later. Respective driving portions 28 and 30, eachconfigured as a thin plate, are provided therein with stepping motorsand reduction gear mechanisms, and controlled by the circuit portion 22so as to drive wheels 36 and 38 fitted onto output shafts 32 and 34 torotate through the stepping motors and the reduction gear mechanisms.Rubber is attached onto an outer circumference of each of the wheels 36and 38. Further, the shape of each of the wheels 36 and 38 is notlimited to a circle but each of the wheels 36 and 38 may be formed intoany one of various shapes such as a triangle, a square, and the like inaccordance with the use.

A spacer 39 supports the power source portion 16, the circuit portion22, and the driving portions 28 and 30 on a housing 39a. The powersource portion 16 and the circuit portion 22 are provided in parallelbetween the pair of driving portions 28 and 30 so that they overlap eachother. Consequently, the power source portion 16 and the circuit portion22 can occupy wide areas considering the whole volume. Therefore, alarge current can be efficiently derived because the internal resistanceof the capacitor and secondary battery can be made low in the powersource portion 16, and the circuit portion 22 is advantageous inmounting of a large-sized IC chip having a complicated function.Further, since the driving portions 28 and 30 are provided separately ofeach other, any magnetic interference or the like is not generatedtherebetween.

Sliding portions 1 and 2 are provided on the bottom portion of the microrobot body 10 so that one of the sliding portions is in contact with arunning ground 3. In the embodiment of FIG. 1, the center of gravity Gof the micro robot body 10 is located below the height of the drivingmeans 36 and sensors 12 and 14, and, at a portion slightly lefthand inthe drawing (hereinafter, referred to "forward") relative to thevertical direction 4 of a driving point 36a where the wheel 36 contactswith the running ground 3 and therefore the sliding portion 1 contactswith the running ground.

FIG. 4 is an explanatory diagram showing a case where the runninggrounded 3 is inclined and the robot body 10 climbs the slope. Here, itis assumed that the climbing ability of the driving portions isapproximate to the limit. In such a situation, the center of gravity Gis located at a portion righthand in the drawing (hereinafter, referredto as "backward") relative to the vertical direction 3 and therefore thesliding portion 2 contacts with the running ground 3. In this case, inorder to improve the climbing ability, it is necessary that not only thetorque of the driving portions is increased but the frictionalresistance of the sliding portion is decreased and the frictional forceof the driving point 36a is increased. That is, in climbing requiring ahigh driving force, it is preferable that the center of gravity islocated so that the whole weight is applied onto the driving point 36ain the state where such a force that a front portion of the micro robotbody 10 will be lifted up by reaction of the driving force of thedriving portions and a force due to the relation between the center ofgravity and the vertical direction are added to each other. In otherwords, it is preferable that the configuration is made such that thecenter of gravity G is located in the front of the vertical directionwhen the running ground is a horizontal path or a downward slope and, onthe contrary, the center of gravity G is located in the rear of thevertical direction in the vicinity of the limit of the climbing ability,that is, it is preferable that the center of gravity G is in positionalrelation with respect to the vertical direction 4 of the driving pointin accordance with the running ground 3.

FIGS. 5 and 6 are a side view and a bottom plan view respectively,showing a robot body according to another embodiment of the presentinvention. In this embodiment, a tactual sense portion 18 and a tail 20are provided for the purpose of charging and balancer.

Although respective sliding portions 18a and 20a are provided in thetactual sense portion 18 and the tail 20 so as to have the samefunctions as those of the foregoing sliding portions 1 and 2, thesliding portions 18a and 20a contact with a running ground 3 in theoutside of a robot body 10. Consequently, since a force acting on thesliding portions 18a and 18a is small so that the frictional resistanceis small and a running loss is therefore less. Bending portions 18b and20b are provided in the tactual sense portion 18 and the tail 20 attheir end portions respectively, the bending portions 18b and 20b beingsmoothly curved relative to the running ground. In such a configuration,the robot body can easily run while sliding even if the running groundis considerably uneven.

The tactual sense portion 18 and the tail 20 have not only flexibilitybut electrical conductivity, and one of them is connected to a powersource portion 16 constituted by an electric double layer capacitor, asecondary battery, and the like. In such a configuration, not onlytreatment can be easily performed because the power source portion 16can be charged through a projection portion of the tactual sense portion18 or the tail 20 but no stress concentrates to thereby hardly causedestruction because of the flexibility thereof.

FIG. 7 is a partially enlarged view showing the side surface of each ofwheels 34 and 36 of the micro robot according to the present invention.Concave and Convex portions 35 and 37 are provided in an outerperipheral portion and high frictional agents 35a and 37a such asrubber, plastic materials, or the like, are stuck. In such aconfiguration, if each of the high frictional agents 35a and 37a is in afluid phase a curing property, the agents are cured into illustratedshapes by surface tension so that only the portions of the highfrictional agents 37a contact with the running ground. Consequently, theload of the micro robot concentrates so that the high frictional agents37a are apt to elastically change so as to obtain large frictionalresistance to thereby improve the climbing ability. Further, the shapesof the concave and convex portions are not limited to those in thisembodiment, but it will do to attach high frictional agents ontocontacting portions in the same manner as in the foregoing case even inthe case where arms or the like are used in place of the wheels.

FIG. 8 is a block diagram showing the circuit portion 22 in detail. ACPU core 40 constituted by an ALU, various registers, and the like isconnected to an ROM 42 carrying programs stored therein, an addressdecoder 44 for the ROM 42, an RAM 46 for storing various data, and anaddress decoder 48 for the RAM 46. A quartz vibrator 50 is connected toan oscillator 52 and an oscillation signal of the oscillator 52 issupplied to the CPU core 40 as a clock signal. Outputs of sensors 12 and14 are inputted to an I/O control circuit 54 and outputted to the CPUcore 40. A voltage regulator 56 is provided for stably supplying acircuit portion 22 with the voltage of a power source portion 16. Amotor driving control circuit 58 performs delivery of the control signalbetween the motor driving control circuit 58 and the CPU core 40 so asto control stepping motors 64 and 66 through motor driving circuits 60and 62 respectively. Power source voltages necessary for the foregoingvarious circuits and the like are supplied from the power source portion16.

The stepping motor 64 is stated as an R-motor in a flowchart of thedrawing which will be described later because the motor 64 is built in adriving portion 30 and disposed at a right side portion in the robotbody 10, and, similarly to this, the stepping motor 66 is stated as anL-motor because the motor 66 is built in the driving portion 28 anddisposed at the left side portion in the robot body 10.

FIG. 9 is a circuit diagram of the sensor 12. The sensor 12 isconstituted by a phototransistor 12a the emitter of which is connectedin series to a pull-down resistor 26. A light detection output is takenout of the emitter of the phototransistor 12b, shaped in the I/O controlcircuit 54, and then supplied to the CPU core 40. Although the circuitdiagram shows an example of the sensor 12, the sensor 14 has quite thesame configuration as that of the sensor 12.

FIG. 10 is a plan view showing the driving portion 30, and FIG. 11 is adevelopment thereof. The stepping motor 64 has an exciting coil 68 and arotor 70 constituted by a magnet. The stator 71 has a pair of recesses73a and 73a formed therein and a pair of concave portions 75a and 75bdisposed outside of the hole which contains the rotor 70. Anelectromagnetic two-pole stepping motor used in an electronic clock isutilized in this embodiment. The rotor 70 drives a pinion 72, the pinion72 drives a pinion 74 through a gear, the pinion 74 drives a pinion 76through a gear, and the thus speed-reduced pinion 76 drives the wheel 38to rotate. The mechanism of FIGS. 6 and 7 utilizes the mechanism of anelectronic clock. Also the mechanism of a driving portion 28 is the sameas that shown in FIGS. 6 and 7. Since the stepping motors 64 and 66 arearranged so as drive the wheels to rotate through speed reduction fromhigh speed rotation as shown in FIGS. 6 and 7, the driving portions 30and 28 can be minimized in size. Further, since the exciting coil 68 isprovided far away from the rotor 70, the driving portions 30 and 28 canbe decreased in thickness and size also in this point of view.

FIGS. 12 A-12G illustrate is a timing-chart showing an example of thefundamental operation of the robot according to the foregoingembodiments. When no light is incident into the sensors 12 and 14, theoutputs thereof are zero V. When light is incident, however, the sensorsoutput voltages corresponding to the quantity of light. The outputvoltages are waveform-shaped with a desired threshold voltage in the I/Ocontrol circuit 54 and then supplied to the CPU core 40 so that themotor driving control circuit 58 supplies forward and backward drivingpulses alternately to the stepping motors 64 and 66 through the drivingcircuits 64 and 66 respectively. Consequently, in a period S₁ duringwhich the sensor 12 is receiving light, the stepping motor 64 operatesto drive the wheel 38 to rotate. In a period S₂ during which the sensor14 is receiving light, the stepping motor 66 operates to drive the wheel36 to rotate. In a period W during which both the sensors 12 and 14 arereceiving light, both the stepping motors 64 and 66 operate to drive thewheels 38 and 36 to rotate respectively.

In the simplest driving example, therefore, when light from the lightsource exists in the field of view A1 (however, except the field of viewA3), the light sensor 12 detects the light so that the stepping motor 64drives the wheel 38 to rotate correspondingly to the light detectionoutput. At this time, the wheel 36 is in the stopped state and thereforethe whole robot body 10 moves to turn left. When light from the lightsource exists in the field of view A2 (however, except the field of viewA3), on the contrary, the light sensor 14 detects the light so that thestepping motor 66 drives the wheel 36 to rotate correspondingly to thelight detection output. At this time, the wheel 38 is in the stoppedstate and therefore the whole robot body moves to turn right. Further,when light from the light source exists in the field of view A3, thelight sensors 12 and 14 detect the light so that the stepping motors 64and 66 operate to drive the wheels 38 and 36 to rotate correspondinglyto the light detection outputs respectively. As a result, the robot body10 moves straight. The robot body 10 is controlled as described above soas to move toward the light source.

Further, the embodiment has shown one combination between the positionof the sensors and the arrangement of the driving portions which move inthe direction of the field of view, but the invention is not limited tothis embodiment.

Although description has been made above as to the operation in the casewhere driving is performed at a predetermined speed when either of thelight sensors 12 and 14 detects light, the driving force becomes high ifdriving is performed with acceleration at the time of starting drive.

FIG. 13 is a flowchart showing the fundamental operation whenacceleration control is performed at the time of starting drive. First,the CPU core 40 sets the clock frequency Rc of driving pulses fordriving the stepping motor 64 to 16 Hz (S1), and next resets the valueRc of a counter for counting the driving pulses (S2). Next, judgment ismade as to whether the light detection output from the sensor 12 existsor not (S3). In the case where the light detection output exists, theCPU core 40 applies driving pulses having the clock frequency Rc todrive the stepping motor 64 and counts the pulses at that time (S4).Judgment is made as to whether the count value Rn is a predeterminedvalue, for example, 15 or not (S5), and if the value is not 15, theforegoing processings (S3) and (S4) are repeated.

After driving corresponding to 15 pulses is carried out with the drivingpulse of the clock frequency Rc (=16 Hz), judgment is made as to whetherthe clock frequency Rc of the driving pulses has reached 128 Hz (themaximum value) or not. If the judgment proves that the frequency doesnot reach the value, the CPU core 40 sets the clock frequency Rc of thedriving pulse, for example, into 32 Hz (S7) and repeats the foregoingoperations in the same manner as in the foregoing case. Then, when theclock frequency Rc of the driving pulse reaches 128 Hz (the maximumvalue) (S6), driving is performed at the driving pulse of the frequencythereafter. When no light detection output from the sensor 12 exists(S3), the stepping motor 64 is stopped (S8).

Although the flowchart shows the relation between the sensor 12(L-sensor) and the stepping motor 64 (R-motor), the relation between thesensor 14 (R-sensor) and the stepping motor 66 (L-motor) is quite thesame as the above relation.

Although description has not been made as to the relation between thesensors 12 and 14 in order to facilitate the understanding on theflowchart of FIG. 13, for example, if the sensor 14 is in the state oflight detection so that the stepping motor 66 is driven to thereby makethe robot body 10 move toward the light source, the sensor 12 comes intothe state of light detection. In such a case, therefore, it is necessaryto make the driving state of the stepping motor 64 driven by the sensor12 coincide with that of the stepping motor 66. If both the drivingstates do not coincide with each other, the robot body 10 becomesimpossible to move linearly at a point of time when the robot body 10 isturned toward the light source. That is, it is impossible to change themovement from turning one to linear one.

FIG. 14 is a flowchart showing the control when the foregoing points areconsidered. Similarly to the foregoing case, the CPU core 40 sets theclock frequency Rc of the driving pulses for the stepping motor 64 to 16Hz (S1) and then resets the value Rc of the counter for counting thenumber of the driving pulses (S2). Next, judgment is made as to whetherthe light detection output of the other sensor 14 exists or not (S2a).In the case where the light detection output of the sensor 14 exists,the clock frequency Lc of the driving pulses of the control system andthe value Ln of the counter at the sensor 14 side are initialized so asto be coincident with the clock frequency Rc of the driving pulses andthe value Rn of the counter at the sensor 12 side respectively. Aftersuch setting, processing is performed in the same manner as in theflowchart of FIG. 13. Although this flowchart shows the operation of thecontrol system for the sensor 12, the operation of the control systemfor the sensor 14 is the same as the above operation.

That is, when the control system for the other sensor is in the drivingstate at the time of starting drive, the driving for the control systemfor the one sensor is started after the driving state of the controlsystem for the other sensor has been taken in as the initial value.Therefore, the direction is changed with acceleration when only one ofthe sensors detects light, and then when both the sensors detect light,both the control systems are made to be in the same driving state atthat moment so that straight moving is performed. Consequently, thechange from turning movement to linear movement can be smoothlyperformed to thereby improve the light response property.

FIGS. 15 -15D illustrates a waveform diagram of the driving pulses. Inorder to improve the driving force when the speed increases at the timeof starting drive as shown in the flowcharts of FIGS. 13 and 14, forexample, the pulse width is enlarged to be 7.8 msec in the case of theclock frequency of 16 Hz. Since the pulse width decreases as thefrequency becomes high, the pulse width is made to be 6.3 msec in thecase of the clock frequency of 32 Hz, 5.9 msec in the case of the clockfrequency of 64 Hz, and 3.9 msec in the case of the clock frequency of128 Hz. Thus, it is possible to supply driving pulse corresponding to arequired driving force to thereby make it possible to perform rationaldriving.

FIG. 16 is a flowchart showing processing in the case of avoiding anobstacle, and FIG. 17 is a diagram for explaining the avoidingoperation. An obstacle sensor constituted by an ultrasonic sensor, anovercurrent sensor, or a touch sensor, or any combination of thosesensors is provided at the front portion of the robot body 10, althoughsuch an obstacle sensor is not illustrated in the drawing.

First, by using the obstacle sensor, judgment is made as to whetherthere is an obstacle or not (S11). If there is no obstacle, work iscontinued as it is (or advancing is made as it is) (S12). If there isany obstacle, on the contrary, the stepping motor 64 or 66 is reverselyrotated (S13). This state is continued for a predetermined time, forexample, 5 minutes (S14). Since this time may be set to a valuesufficient for changing the direction, the time is not limited to theabove-mentioned value. Alternatively the distance of movement may be setin place of the time. Thereafter, judgment is made by means of theobstacle sensor again as to whether there is any obstacle or not (S11).By repeating such processing, the direction is changed if there is anyobstacle to thereby avoid the obstacle.

FIG. 18 is a flowchart showing the processing in the case wherecollision is detected on the basis of an induced voltage in the steppingmotor and an obstacle is avoided, and FIG. 19 is a diagram forexplaining the avoiding operation. The stepping motors 64 and 66 areturned on (S21) and judgment is made as to whether the stepping motor 64is rotating in this state or not (S22). If the motor 64 is rotating,judgment is made as to whether the stepping motor 66 is rotating or not(S23). If also the stepping motor 66 is rotating, it is concluded thatthere is no obstacle and work is continued (S24). Further, the method ofdetection as to whether the stepping motors 64 and 66 are rotating ornot is performed by utilizing the fact that a large voltage is inducedin the exciting coil 68 when the motor rotates and, on the contrary, asmall voltage is induced in the exciting coil 68 when the motor is notrotating.

FIGS. 20 A-20B illustrate a timing-chart showing the method of detectionas to whether the stepping motor is rotating or not. When the steppingmotor is in the rotating state as shown in the drawing and in the casewhere the rotor 70 rotates after application of the driving pulses, aninduced voltage is induced and an induced current flows in the excitingcoil 68 as the rotor 70 rotates. The value of the induced current isdetected, for example, by using a comparator so that the rotating statecan be grasped. When the stepping motor is not in the rotating state, onthe contrary, the rotor 70 never rotate after application of the drivingpulses so that no induced voltage is induced and no induced currentflows in the exciting coil 68. Thus, it is possible to detect the factthat the stepping motor is not in the rotating state.

In the case where it is concluded that the stepping motor 64 is notrotating in detection of rotation of the stepping motor 64 (S22), thedriving for the stepping motors 64 and 66 is stopped (S25) and thestepping motors 64 and 66 are made to rotate reversely (S26). Thereverse driving state is continued, for example, for 5 minutes (S27).Next, the stepping motor 64 which had been concluded so as to to be inthe not-rotating state is driven again (S28) and the state is continued,for example, for 5 minutes (S29). Then, the operation is returned to thefirst processing (S21). Further, in the case where the stepping motor 66is concluded so as not to be rotating in detection of rotation of thestepping motor 66 (S23), the driving for the stepping motors 64 and 66are stopped (S30) and the stepping motors 64 and 66 are reverselyrotated (S31). The reverse driving state is continued, for example, for5 minutes (S32). The stepping motor 66 is driven again (S33) and thisstate is continued for 5 minutes (S29). Thereafter, the operation isreturned to the first processing (S21).

As described above, the fact that the stepping motors 64 and 66 arerotating or not is detected, and if it is concluded that one of thestepping motors 64 and 66 is not rotating, the driving for the steppingmotors is once stopped and then the stepping motors are reverselyrotated. Next, the one stepping motor which is concluded so as to be notrotating is rotated again. For example, when the robot body 10 collidesagainst a wall and a state where the stepping motor 66 is not rotatingis generated, the driving for the stepping motors 64 and 66 are stoppedonce and the stepping motors are reversely rotated so as to retreat therobot body 10. Then, the stepping motor 66 is driven to thereby changethe direction. Thereafter, the stepping motors 64 and 66 are driven soas to make the robot body 10 move straight. Consequently, the robot body10 can travel while avoiding an obstacle.

Although description has been made as to avoidance of an obstacle in thestate where the stepping motors 64 and 64 are being driven in accordancewith the flowchart of FIG. 18, the same processing is performed also inthe case where either one of the stepping motor 64 and 66 is beingdriven. When, for example, the stepping motor 64 is being driven, it ispossible to cope with a trouble in such a manner that the stepping motor64 is driven in the processing (S21) in FIG. 18, and then processing(S22) and processings (S25) through (S29) are performed. Similarly tothis, also in the case where the stepping motor 66 is being driven, itis possible to cope with a trouble in such a manner that the steppingmotor 66 is driven in the processing (S23) in FIG. 18 and then theprocessing (S23), the processings (S30) through (S33), and theprocessing (S29) are performed.

FIGS. 22 through 23 are a front elevation, a side elevation, and a rearelevation showing a micro robot according to a further embodiment of thepresent invention, respectively. The configuration is made such thatsensors 82a through 82d are provided on a front portion of a robot bodyand screws 84a through 84d are provided on a rear portion thereof sothat driving in a fluid can be performed. Since the four, left, right,upper and lower screws 84a through 84d are provided so as to be drivenby stepping motors respectively, it is a matter of course that the robotbody 80 can be controlled in the left/right direction as well as in theup/down direction. Further, the robot of FIG. 1 or 5 has only two motorsand therefore respective driving pulses are supplied to the motors inthe same timing. In this embodiment, however, the timing of drivingpulses is shifted from each other by means of a circuit shown in FIG. 24because the four screws 84a through 84d are provided and it is thereforenecessary to provide four stepping motors for driving the screws 84athrough 84d and because if the stepping motors are driven on the basisof the driving pulses of the same timing, the consumption of a powersource portion 16 remarkably increases.

FIG. 24 is a block diagram showing circuits in the periphery of a motordriving circuit. In the circuit diagram, motor driving circuits 86 and88 are provided in addition to motor driving circuits 60 and 62 of FIG.8 and the driving circuits drive stepping motors 64, 66, 90, and 92respectively. Further, the stepping motors 64, 66, 90, and 92 drive thescrews 84a through 84d to rotate respectively. In this embodiment, phasedifference circuits 94 through 100 for controlling the phases of themotor driving circuits 60, 62, 86, and 88 are provided and the phaseadjustment angles of the phase difference circuits 94 through 100 aredifferent from each other so that the driving pulses are not producedfrom the motor driving circuits 60, 62, 86, and 88 in the same timing.

Although description has been made as to the example in which light isdetected by means of sensors so that the robot body advances toward thelight in the foregoing embodiments, a subject to be detected is notlimited to light, it may be magnetism, heat (infrared rays), sound, anelectromagnetic wave, and so on. Moreover, the robot body can becontrolled so as not to move toward a subject to be detected but to runaway therefrom. In this case, in the embodiment of FIG. 1 or 5, thesensor 12 is turned off to thereby drive the stepping motor 64 so as todrive the wheel 38. The sensor 14 is turned off to thereby drive thestepping motor 66 so as to drive the wheel 36. When both the sensors 12and 14 are in the turned-on state, the stepping motors 64 and 66 arereversely driven to thereby reversely drive the wheels 38 and 36respectively so that the robot body 10 is retreated or made to run away.Further, if two kinds or more of subjects to be detected are preparedand if control is made so that the robot body 10 moves toward onesubject to be detected and run away from the other subject to bedetected, it is possible to perform delicate control. It is a matter ofcourse that this control can be applied to the robot body 100 of FIGS.21 through 23.

Not only the movement direction of the robot body is determined on thebasis of a subject such as light or the like to be detected, but, forexample, a movement locus may be programmed in advance so as to performcontrol on the basis of the movement locus. Alternatively, the movementlocus may be controlled by application of instruction from the outside.Moreover, a suitable combination of the foregoing controls may beperformed while a studying function is given thereto.

FIG. 25 is a top plan view showing a micro robot according to a stillfurther embodiment of the present invention. A pair of direction controlsensors 12 and 14 are provided at a front portion of a robot body 10 asshown in the drawing, and a work control sensor 15 is further providedat an upper portion of the robot body 10 as shown in the drawing so thatworking instruction is received from the outside through the workcontrol sensor 15 as will be described later. Moreover, the bottom planview of the robot body 10 is the same as that of the embodiment of FIG.6.

FIG. 26 is a block diagram showing a circuit portion 22 of theembodiment of FIG. 25 in detail. A CPU core 40 constituted by an ALU,various registers, and the like is connected to an ROM 42 carryingprograms stored therein, an address decoder 44 for the ROM 42, an RAM 46for storing various data, and an address decoder 48 for the RAM 46. Aquartz vibrator 50 is connected to an oscillator 52 and an oscillationsignal of the oscillator 52 is supplied to the CPU core 40 as a clocksignal. Outputs of direction control sensors 12 and 14 and an output ofa work control sensor 15 are inputted to an I/O control circuit 54 andoutputted to the CPU core 40. A motor driving control circuit 58performs delivery of control signals between the motor driving controlcircuit 58 and the CPU core 40 so as to control stepping motors 64 and.66 through motor driving circuits 60 and 62 respectively and so as tocontrol a work actuator 67 through an actuator driving circuit 63.

The stepping motor 64 is stated as an R-motor in a flowchart of thedrawing which will be described later because the motor 64 is built in adriving portion 30 and disposed at a right side portion in the robotbody 10, and, similarly to this, the stepping motor 66 is stated as anL-motor because the motor 66 is built in the driving portion 28 anddisposed at a left side portion in the robot body 10.

FIG. 27 is a flowchart showing the control operation of the circuitportion of FIG. 26. Movement is performed toward a light-emitting targeton the basis of the direction control sensors 12 and 14, and the worksensor 15 receives instruction from an operator so as to performpredetermined work.

First, the CPU core 40 judges whether the direction control sensor 12 isin the turned-on state because it detects light or not (S41). If thesensor 12 is in the turned-on state, it is concluded that a light sourceis located on the left and the stepping motor 64 is driven to therebydrive the wheel 38 to rotate so as to perform left turning (S42). If thedirection control sensor 12 is in the turned-off state (S41), on thecontrary, driving of the stepping motor 64 is stopped (S43). Next,judgment is made as to whether the direction control sensor 14 is in theturned-on state because of detection of light or not (S44), and if thesensor 14 is not in the turned-on state, driving of the stepping motor66 is stopped (S45). If the direction control sensor 14 is turned on byrepetition of the foregoing processing (S44), the stepping motor 66 isdriven (S47). The robot body 10 moves toward the light source throughsuch operation. Next, judgment is made as to whether the work controlsensor 15 detects light or not (S47), and in the state where the workcontrol sensor 15 does not detect light the robot body advances throughrepetition of the foregoing operation. If the work control sensor 15 isin the turned-on state because of detection of light, the actuatordriving circuit 63 controls the work actuator 67 to perform desired work(S48).

FIG. 28 is a flowchart showing the operation when the work controlsensor 15 is not mounted in FIGS. 25 and 26. Also in this embodiment,first, the CPU core 40 judges whether the direction control sensor 12 isin the turned-on state because it detects light or not (S51). If thesensor 12 is in the turned-on state, it is concluded that a light sourceis located on the left and the stepping motor 64 is driven to therebydrive the wheel 38 to rotate so as to perform left turning (S52). If thedirection control sensor 12 is in the turned-off state (S51), on thecontrary, driving of the stepping motor 64 is stopped (S53). Next,judgment is made as to whether the direction control sensor 14 is in theturned-on state because of detection of light or not (S54), and if thesensor 14 is not in the turned-on state, driving of the stepping motor66 is stopped (S55). If the direction control sensor 14 is turned on byrepetition of the foregoing processing (S54), the stepping motor 66 isdriven (S57). The robot body 10 moves toward the light source throughsuch operation. Next, judgment is made as to whether the stepping motors64 and 66 are rotating or not (S57), and in the state where the steppingmotors 64 and 66 are rotating, the robot body advances throughrepetition of the foregoing operation. When the robot body 10 reachesand collides a predetermined point, the stepping motors 64 and 66 do notrotate at that moment. It is therefore concluded the not-rotation meansthat the robot body reaches a predetermined position, and then theactuator driving circuit 63 controls the work actuator 67 to performdesired work (S58).

Further, judgment is made as to whether the stepping motors 64 and 66are rotating or not as follows. When the stepping motor is in therotating state, the rotor 70 rotates after the driving pulse is suppliedto the exciting coil 68 and an induced voltage is induced so that aninduced current flows in the exciting coil 68 with the rotation of therotor 70. The value of the induced current is detected by means of acomparator or the like so as to detect the fact that the stepping motoris in the rotating state. When the stepping motor is not in the rotatingstate, the rotor 70 does not rotate after application of the drivingpulse and therefore no induced voltage is induced in the exciting coil68. It is detected from this fact that the stepping motor is not in therotating state.

FIG. 29 is a block diagram showing another embodiment of the circuitportion 22 in detail. In this embodiment, a reception sensor 102, atransmission element 104, and a detection element 106 are connected, asthe sensors, to an I/O control circuit 54. FIG. 30 is a top plan viewshowing a robot body 10 in which the reception sensor 102 and thetransmission element 104 are disposed in the illustrated position. Inthis embodiment, the reception sensor 102 is configured so as to receivemoving and working instruction. A pulse signal or the like having apattern corresponding to the instruction (a straight-moving instruction,a right-turning instruction, a left-turning instruction, a retreatinginstruction, a working instruction, or the like) is supplied to thelight reception sensor 102 by utilizing, for example, infrared rays. Thedetection element 106 is constituted, for example, by an image sensor, atactual sensor, or the like, and information detected in the detectionelement 106 is transmitted to the operation side by using thetransmission element 104.

FIG. 31 is a flowchart showing the control operation of the circuitportion of FIG. 29. First, when the reception sensor 102 receives astraight-moving instruction from the operation side, the CPU core 40detects the instruction (S61) and drives the stepping motors 64 and 66so as to perform straight moving (S62). When the reception sensor 102receives a right-turning instruction from the operation side, the CPUcore 40 detects the instruction (S63) and drives the stepping motor 66so as to perform right-turning (S64). When the reception sensor 102receives a left-turning instruction from the operation side, the CPUcore 40 detects the instruction (S65) and drives the stepping motor 64so as to perform left turning (S66). When the reception sensor 102receives a retreating instruction from the operation side, the CPU core40 detects the instruction (S67) and reversely drives the steppingmotors 64 and 66 so that the robot body 10 is retreated (S68). Whenthere is not any movement control instruction, driving of the steppingmotors 64 and 66 is stopped (S69). Next, the CPU core 40 judges whethera working instruction is supplied or not (S70). If no workinginstruction is supplied, the processing is completed as it is. If aworking instruction is supplied, on the contrary, the actuator drivingcircuit 63 controls the work actuator 67 to perform desired work (S71).Thereafter, the CPU core 40 judges whether a transmission instruction issupplied through the reception sensor 102 or not (S72). If atransmission instruction is supplied, information detected, for example,by means of the detection element 106 is coded and transmitted to theoperation side through the transmission element 104 (S73). The foregoingprocessing is cyclically repeated.

Various work may be listed as the foregoing work, and examples of thework are as follows.

(1) Ejection of a medical fluid with a micro pump.

(2) Sensing of temperature, pressure, components, images, and the like.

(3) Work by hands (for example, carrying parts or the like).

(4) Data storage and transmission.

(5) Action by a micro robot itself (for example, boring, working by itsself-destruction, integral working by robots with various functions).

(6) Taking and throwing-away of samples.

FIG. 32 is a section showing an example in which the micro robotaccording to the present invention is applied to an endoscope. Thisdevice has a plunger 110 to be controlled by a circuit portion 22 andthe plunger 110 drives a piston 112 provided at a front portion thereof.A micro pump 114 is constituted by the plunger 110 and the piston 112,and a medical fluid 116 is injected into a pipe through a nozzle 118 bymovement of the piston 112. A photovoltaic element 120 is attached on anouter periphery of the robot. Light from a light emitting portion is ledthrough optical fibers 122, reflected from a mirror 124, furtherreflected by a pipe inner wall 126, and led to a light detection portionthrough the passage reverse to the foregoing one so as to perform thefunction of the endoscope. The light reflected from the pipe inner wall126 is partially supplied also to the photovoltaic element 120 so as tocharge a power source portion (not shown) of a circuit portion 22.Further, although the configuration of this embodiment is the same asthat of the embodiment described in FIGS. 25 and 26 in the fundamentalthinking, the members such as the sensors 12 and 14, the wheels 36 and38, the stepping motors 64 and 66, and the like are not required to beprovided.

In this embodiment, the circuit portion 22 is provided therein with adecoder and the decoder is connected in parallel to the power sourceportion connected to the output of the photovoltaic element 120 so as totake and analyze a control signal contained in a charged current. Inthis embodiment, therefore, a working instruction is received from theoperation side through the optical fibers 122 at a desired positionwhile observation of the inside of the pipe is performed as theendoscope, and the circuit portion 22 takes in the instruction throughthe photovoltaic element 120 to drive the plunger 110 to eject themedical fluid 124 from the nozzle 118.

FIG. 33 is a bottom view of a micro robot according to anotherembodiment of the present invention, and FIG. 34 is a side view thereof.In the micro robot in this embodiment, a micro pump 130 is built in themicro robot body shown in FIG. 25, and a nozzle 132 is provided in thefront portion thereof. In this embodiment, the micro pump 130 is drivento inject medicinal fluid from the nozzle 132, for example, in the work(S48) in the flowchart of FIG. 27, the work (S58) in the flowchart ofFIG. 28, and the work (S71) in the flowchart of FIG. 31.

FIG. 35 is a side view of a micro robot according to another embodimentof the present invention, and FIG. 36 is a bottom view thereof. In themicro robot in this embodiment, a hand mechanism is provided in a robotbody 10. An upper motor unit 140 is provided in the upper portion of therobot body 10 so as to rotate an upper pinion 142 so that the upperpinion 142 engages with an upper gear 144 to drive an upper arm 146supported rotatably by a shaft 152. A lower motor unit 148 is providedin the lower portion of the robot body 10 so as to rotate a lower pinion149 so that the lower pinion 149 engages with a lower gear 150 to drivea lower arm 154 supported rotatably by the shaft 152. These upper andlower arms 146 and 154 constitute a hand 156.

FIG. 37 is a block diagram illustrating the details of a circuit portion22 of the micro robot of the embodiment of FIGS. 35 and 36. Thisembodiment is basically the same as that of the circuit diagram of FIG.26, except that upper and lower motor drivers 160 and 162 are provided.The upper motor driver 160 drives and controls an upper motor 164 builtin the upper motor unit 140, and the lower motor driver 162 drives andcontrols a lower motor 166 built in the lower motor unit 148. Preferablythe upper and lower motors 164 and 166 are constituted by steppingmotors, and in such a case it is easy to drive the upper and lowermotors 164 and 166 synchronously.

FIG. 38 is a flowchart illustrating the control operation of the microrobot in the embodiment of FIGS. 35 to 37. First, if a work controlsensor 15 receives a control instruction, a CPU core 40 judges whetherthe instruction is an instruction to move up the arm or not (S81). Ifthe instruction is an instruction to move up the arm, the upper motor164 is rotated counterclockwise by the upper motor driver 160 (S82).Consequently the upper arm 146 is rotated clockwise. Next, the lowermotor 166 is rotated counterclockwise by the lower motor driver 162(S83). Consequently the lower arm 154 is rotated clockwise. The hand 156is moved up as shown in FIG. 39 by rotating both the upper and lowerarms 146 and 154 clockwise in such a manner.

On the contrary, if the CPU core 40 receives an instruction to move downthe arm (S84), the upper motor 164 is rotated clockwise by the upperdriver 160 (S85). Consequently the upper arm 146 is rotatedcounterclockwise. Next, the lower motor 166 is rotated clockwise by thelower driver 162 (S86). Consequently the lower arm 154 is rotatedcounterclockwise. The hand 156 is moved down by rotating both the upperand lower arms 146 and 154 counterclockwise in such a manner.

On the other hand, if the CPU core 40 receives an instruction to openthe arm (S87), the upper motor 164 is rotated counterclockwise by theupper driver 160 (S88). Consequently the upper arm 146 is rotatedclockwise. Next, the lower motor 166 is rotated clockwise by the lowerdriver 162 (S89). Consequently the lower arm 154 is rotatedcounterclockwise. Thus, the upper and lower arms 146 and 154 are openedas shown in FIG. 40 by rotating the upper arm 146 clockwise and thelower arm 154 counter-clockwise.

On the contrary, if the CPU core 40 receives an instruction to close thearm (S90), the upper motor 164 is rotated clockwise by the upper driver160 (S91). Consequently the upper arm 146 is rotated counterclockwise.Next, the lower motor 166 is rotated counterclockwise by the lowerdriver 162 (S92). Consequently the lower arm 154 is rotated clockwise.Thus, the upper and lower arms 146 and 154 are closed by controlling theupper and lower arms 146 and 154 to approach each other.

FIG. 41 is a conceptual diagram of a micro robot according to anotherembodiment of the present invention, and FIG. 42 is a side view thereof.A robot body 10 includes a work motor 200 as illustrated, and this workmotor 200 is constituted by a motor stator 202 and a rotor 204. Thisrobot body 10 is disposed in a non-magnetic pipe 206, and thisnon-magnetic pipe 206 is filled with a fluid. A coil stator 208 isdisposed outside the non-magnetic pipe 206, and a coil 210 is wound onthe coil stator 208.

FIG. 43 is a diagram illustrating the details of the work motor 200. Apair of inner notches 202a are provided in the inner circumferentialportion of the motor stator 202, and a pair of outer notches 202b areprovided in the outer circumferential portion, so that the positions ofthe inner notches 202a are shifted from the positions of the outernotches 202b in the circumferential direction as illustrated. The rotor204 is constituted by a magnet, which is magnetized into two poles, Nand S poles. If a magnetic field is applied from the outside, a magneticflux 212 passes through the motor stator 202 as illustrated.

FIGS. 43 through 46 are diagrams illustrating the principle of operationof the work motor 200. FIG. 44 is a diagram illustrating the state inwhich a magnetic field is not applied from the outside. The boundarypoints of the N and S poles of the rotor 204 are stable while they arein opposition to the inner notches 202a in this state. Next, if amagnetic field is applied as shown in FIG. 45, the rotor 204 rotates,but the portions of the motor stator 202 corresponding to the outernotches 202b are so narrow to be saturated magnetically if a strongmagnetic field is applied, so that the magnetic field in these portionsis so weak that the above-mentioned boundary points of the rotor 204 arestabilized in the portions corresponding to the outer notches 202b. Ifapplication of the magnetic field from the outside is stopped afterthat, the above-mentioned boundary points are stabilized while they arein opposition to the inner notches 202a as shown in FIG. 46. It isunderstood that the rotor 204 is thus rotated by half a rotation fromFIG. 44 to FIG. 46. Next, the rotor 204 is further rotated by half arotation if a magnetic field is applied from the opposite direction. Therotor 204 is rotated continuously by thus application of oppositemagnetic fields alternately. Although an example of rotating a rotorcounterclockwise has been described, it is possible to rotate a rotorclockwise in the same manner. Further, this principle of operation of amotor itself can be applied to the stepping motors 64 and 66 in theabove-mentioned embodiments, and so on.

Since the principle of operation of the work motor 200 has been madeapparent, next the operation of the apparatus in FIGS. 41 and 42 will bedescribed. If a positive/negative exciting current is fed to the coil210, a magnetic flux corresponding thereto is generated in the coilstator 208, and the magnetic flux passes through the non-magnetic pipe206, and reaches to the motor stator 202, so that the rotor 204 isrotated by the above-mentioned principle of operation. With the rotationof the rotor 204, it is possible to function as a micro pump, to rotatea not-shown screw as propulsion, or to make a stream of fluid. Or it isalso possible to rotate a not-shown cutter to cut off an aimed portion.

Particularly in this embodiment, if the coil stator 208 is moved in thelongitudinal direction of the non-magnetic pipe 206, the work motor 200itself is moved along the movement of the coil stator 208 by themagnetic force caused by the magnetic field. It is therefore possible tocontrol the position of the micro robot body 10 by applying a magneticfield from the outside. Further it is not necessary to mount the microrobot body 10 with means (accumulator) for storing energy for drivingthe work motor 200 since the work motor 200 can be driven by applying amagnetic field from the outside. Not one coil stator 208 but a pluralitythose coil motors may be provided along the longitudinal direction ofthe non-magnetic pipe 206 to drive a plurality of robot bodies 10sequentially. Further, it is not necessary to make the coil 210single-phase, and it may be constituted by a multi-phase coil such asthree-phase one or the like. In such a case, the motor stator 202 and soon should be made to have configurations corresponding to the number ofphases of the coil.

The stepping motors in the above-mentioned embodiments except for theembodiment of FIG. 41 may be constituted by ultrasonic motors or thelike. Further, a micro robot may be constituted by the desiredcombination of elements in the above-mentioned embodimentscorrespondingly to necessity.

Next, a charging mechanism for the power source 16 will be described.

FIG. 47 is a block diagram illustrating the details of the circuitportion 22 to which a charging mechanism by electro-magnetic inductionis added. The output of a charging circuit of a motor driving circuit 62is connected to a power source portion 16, and a voltage regulator 56 isconnected to this power source portion 16. This voltage regulator 56 isconstituted by a boosting circuit 300 and a voltage limiter 302.

FIG. 48 is a circuit diagram illustrating the details of the motordriving circuit in this embodiment. Motor drivers 304, 306, 308 and 310are H-connected to an exciting coil 68 as shown therein, and diodes 312,314, 316 and 318 are connected to the respective drivers in parallel andin reverse direction. Further, switches 320 and 322 for detecting an ACmagnetic field are connected in the both ends of the exciting coil 68,so that a closed circuit is formed for the exciting coil 68 if theseswitches 320 and 322 are closed. Further, the both ends of the excitingcircuit 68 are led to invertors 324 and 326 for detecting a magneticfield, and the outputs thereof are led to a motor driving controlcircuit 58 through an OR circuit 328. Stationarily the drivers 304 and310 and the drivers 308 and 306 are driven alternately to apply anexciting current to the exciting coil 68 to drive a stepping motor 66,but if all the drivers 304, 306, 308 and 310 are turned off at the timeof charging operation, and the exciting coil 68 suffers theelectromagnetic induction from a charging coil of a charging stand whichwill be described later, an induced voltage is rectified by the diodes312, 314,316 and 318, and led to the power source portion 16 to performcharging operation. The diodes 312, 314, 316 and 318 provided outsidethe drivers 304, 306, 308 and 310 can be omitted if the drivers 304,306, 308 and 310 are constituted by FETs as illustrated, so that diodesincluded therein equivalently have enough functions.

FIG. 49 is a graph of the discharge characteristic of an electric doublelayer capacitor 334 constituting the power source portion 16, and FIG.50 is a circuit explanation diagram illustrating the details of thevoltage regulator 56. In FIG. 50, a high capacitance capacitor 334 and alimiter switch 330 are provided, and a capacitor 360 is further includedas another power source. Means for charging from the capacitor 334 tothe capacitor 360 while boosting the voltage thereof is shown in theportion surrounded by a broken line 335. The means 335 for charging fromthe capacitor 334 to the capacitor 360 while boosting the voltage isconstituted by capacitors 340 and 350, and switches 336, 338, 342, 344,346, 348 and 352. A source voltage is supplied from the capacitor 360 tothe respective portions of the control portion 22. A detector 332detects the voltage of the capacitor 334.

Next the operation of the circuit of FIG. 50 will be described.

After the large capacitance capacitor 334 is fully charged, the voltagesof the capacitors 334 and 360 are the same when the voltage of thecapacitor 334 is not lower than 1.2 V. When the voltage of the capacitor334 is in a range of from 1.2 V to 0.8 V, it is boosted by 1.5 times bythe boosting means 335 to charge the capacitor 360. This operation isperformed in the period from t₁ to t₃ in FIG. 49. Therefore, the voltageof the capacitor 360 at this time is in a range of from 1.8 V to 1.2 V.When the voltage of the capacitor 334 is in a range of from 0.8 V to 0.6V, it is boosted by two times by the boosting means 335 to charge thecapacitor 360. This operation is performed in the period from t₃ to t₄in FIG. 49. The voltage of the capacitor 360 at this time is in a rangeof from 1.6 V to 1.2 V.

When the voltage of the capacitor 334 is not higher than 0.6 V, it isboosted by three times by the boosting means 335 to charge the capacitor360. This operation is performed after t₄ in FIG. 49. FIG. 49 shows thisstate. The voltage illustrated with a solid line is the voltage of thecapacitor 360 in FIG. 50, and the voltage illustrated with a broken lineis the voltage of the capacitor 334.

Next the operation of the boosting means 335 will be described.

At the time of boosting, charging is first performed from the capacitor334 to the capacitors 340 and 350, and then the capacitor 360 is chargedby the capacitors 334, 340 and 350. That is, the operation shown inFIGS. 51A and 51B through FIGS. 53A and 53B therefore is repeated toboost and charge.

The diagrams of FIGS. 51 A and 51B show the case of boosting by 1.5times;

The diagrams of FIGS. 52 A and 52B show the case of boosting by 2 times;and

The diagrams of FIGS. 53 A and 53B show the case of boosting by 3 times.

Such switching is executed by switching the switches 336, 338, 342, 344,346, 348 and 352.

As has been described, according to this embodiment, the time possibleto operate is expanded from the time t₂ to the time t₅ in FIG. 49.Further, while the voltage of the capacitor 334 cannot be used in theconventional case if it is not from 0.9 V to 1.8 V, it is possible touse it from 0.3 V to 1.8 V according to this embodiment, so that it isunderstood that the energy accumulated in the capacitor 334 can be usedeffectively.

Although the boosting means 335 includes three kinds of boosting meansof 1.5 times, 2 times and 3 times in this embodiment, and they areswitched through an electric signal by the signal detection portion 332so as to be used, the present invention is not to be limited to thisthree kinds, and many variations can be considered, such as providingonly one kind or many kinds, or various boosting factors. Further,although voltage detection is performed by detecting the voltage of thecapacitor 334 (1.8 V, 1.2 V, 0.8 V, 0.6 V) in this embodiment, not tosay, the voltage of the capacitor 360 may be detected (1.8 V, 1.2 V) sothat it is compared with the content of the boosting means 335 to decidethe boosting state. This method has an advantage that the detectionvoltage can be reduced.

FIG. 54 is a perspective view of a charging stand which is applied tothe above-mentioned micro robot. As shown therein, an energy supplydevice 372 is provided near a signal generator 370 which emits, forexample, infrared rays, and a charge area 374 is formed in the upperportion of the energy supply device 372.

FIG. 55 is a block diagram illustrating the structure of the energysupply device 372. The output of an oscillator 376 is amplified by anamplifier 378 to excite a charging coil 380. The frequency of theexciting current of this charging coil 380 is established into thefrequency higher than the frequency which can be followed by a steppingmotor.

FIG. 56 is a flowchart illustrating the operation at the time ofautomatic charge. The CPU core 40 receives the voltage value of thepower source portion 16, judges whether it is higher than apredetermined reference voltage or not (S111), and continues a normaloperation if it is higher (Sl12). If the voltage of the power sourceportion 16 is lower than the predetermined reference voltage VL, acharge operation is started. First, the robot body 10 is rotated once asit is. For example, if the robot body 10 starts turning to the left, theCPU core 40 judges whether the sensor 12 is in the turned-on state ornot (Sl13), and concludes the signal generator 370 is in the left if thesensor 12 is in the turned-on state, so that the stepping motor 64 isdriven (Sl14). Consequently the wheel 38 is driven to rotate to performleft turning. The CPU core 40 also judges whether the sensor 14 is inthe turned-on state or not (Sl15), and concludes that the signalgenerator 370 is in the right if the sensor 14 is in the turned-onstate, so that the stepping motor 66 is driven (Sl16). Consequently thewheel 36 is driven to rotate to perform right turning. Each of thesesensor 12 and 14 includes two elements: one element is used for guide inresponse to, for example, normal light, and the other element is usedfor searching the charge area 374 in response to, for example, onlyinfrared rays from the signal generator 370.

Next, the switches 320 and 322 in FIG. 48 are closed, so that theexciting coil 68 generates an induced voltage in response to a magneticfield generated by the charging coil 380 if the robot body 10 reachesthe charge area 374. This induced voltage is supplied to the CPU core.40through the invertors 324 and 326 and the OR circuit 328, and it isdetected therein to detect an AC magnetic field (Sl17). The robot body10 is on the charge area 174 when an AC magnetic field is detected, sothat driving of the stepping motors 64 and 66 is stopped (Sl18). Theexciting coil 68 generates an induced voltage in response to a magneticfield generated by the charging coil 380, and the induced voltage isrectified by the diodes 312, 318, 316 and 306, and led to the powersource portion 16, so that a charging current is supplied to the powersource portion 16. Then, the CPU core 40 receives the voltage of thepower source portion 16, judges whether the received voltage is higherthan a predetermined value VH or not (S119), and moves to a normaloperation again if the received voltage becomes higher (Sl12).

The signal generator 370 of the charging stand may be means forgenerating ultrasonic waves, magnetism, or the like. In such a case, itis necessary to mount the robot body side with a sensor for detectingit. Further, the robot body 10 may be made to move upon detection ofmagnetism, light, heat, or the like generated from the energy supplydevice 372. In such a case, the signal generator 370 is not necessary.

Further, the energy supply device 372 may be operated after the robotbody 10 reaches the charge area 374, and it is possible to reduce energyin such a case.

FIGS. 57 through 60 are diagrams illustrating a micro robot according toanother embodiment of the present invention; FIG. 57 is a diagram viewedfrom the front; FIG. 58 is a diagram viewed from the back; FIG. 59 is asectional view taken on line 59--59; and FIG. 60 is a diagram forexplaining the function of an arm. The micro robot in this embodiment isnot only to obtain a propulsive force by rotating a fin in the fluidflowing in a pipe, but also to generate electricity for charge by use ofthe flow of the fluid at the time of charge. Four arms 400 are attachedto the front portion of a robot body 10, and a fin 402 having outerteeth 404 in its outer circumference portion is attached to the rearportion. Further, the fin 402 is covered with a cover portion 406. Thefin 402 is coupled with a stepping motor 66 through a pinion 408. Oneend portion of the arms 400 is arranged to be driven by a plunger 410,so that the arms 400 are expanded if the plunger 410 is pulled, and therobot body 10 stops in the fluid if the end portion of the arms 400 ispushed on the inner wall of the pipe.

The configuration of a circuit 22 in this embodiment is basically thesame as that shown in FIG. 47, providing that the stepping motor 64 inFIG. 47 is replaced by the plunger 410. In a normal operation state, thefin 402 is driven to rotate by the stepping motor 66 so that the robotbody 10 advances in the fluid. If the voltage of a power source portion16 is lower than a predetermined reference value VL, driving of thestepping motor 66 is stopped, and the plunger 410 is pulled to expandthe arms 400. Consequently the robot body 10 stops in the fluid. If thefluid flows in the pipe in such a state of stoppage, the fin 402 isrotated to rotate a rotor 70 of the stepping motor 66 so that an inducedvoltage is generated in an exciting coil 68, rectified in the samemanner as in the above-mentioned embodiment, and led to the power sourceportion 16. Thus, a charging current is supplied to the power sourceportion 16. If the voltage of the power source portion 16 charged insuch a manner becomes not lower than a predetermined reference voltageVH, the plunger 410 is returned to close the arms 400 to release therobot body 10 from the state of stoppage, and so that the stepping motor66 is driven to make the robot body 10 start advancing again.

FIG. 61 is a block diagram illustrating the structure of a controlportion in the case of charging by means a photo-electromotive element.For example, a solar cell 412 is included as a photo-electromotiveelement, and the output of this solar cell 412 is supplied not only tothe power source portion 16 through a limiter 302 (refer to FIG. 47) ofa voltage regulator 56, but also to a CPU core 40 through a decoder 416.

FIG. 62 is a flowchart illustrating the operation of the embodiment ofFIG. 61. Charging is performed by the solar cell 412 even at the time ofa normal work in this embodiment. If the voltage of the power sourceportion 16 is lower than a predetermined reference voltage VL (S121),the stepping motors 64 and 66 are driven (S122), and such a state iscontinued till the rotation of these motors becomes not be detected(S123) and (S124). That is, the stepping motors 64 and 66 are driventill the robot body 10 collides with a wall or the like to thereby putthe robot body 10 aside to the corner, and in such a state charging isperformed for a certain time, for example, about 100 seconds (S125). Ifthe voltage of the power source portion 16 becomes higher than thepredetermined reference voltage VL (S121), a normal work is performedagain (S122). In this embodiment, it is not only possible to supplyenergy from a luminous element on the luminous side by controlling theluminous element, but it is also possible to supply a control signal bysuperimposing the control signal on the luminous energy. On the side ofthe robot body 10, the output of the solar cell 212 is analyzed by thedecoder 416, and then taken into the CPU core 40.

Although an example by use of the solar cell 412 has been described inthe embodiment of FIG. 61, this solar cell may be replaced by athermoelectric generation element. The thermoelectric generation elementis to generate electricity by the difference of temperature, so that thethermoelectric generation element can generate electricity continuouslyif absorbing heat and producing heat are repeated alternately on theside of energy supply (by driving a heat absorbing/producing element inthe charge stand). In such a case, it is necessary to provide arectifying circuit in the charging circuit 214 since the output of thethermoelectric generation element repeats positive and negativepolarities alternately. A rectifying circuit is necessary not only insuch a case, but also in the case of providing a charging coil in steadof the solar cell 212 so as to charge the power source portion 16without using the exciting coil 68.

FIG. 63 is a flowchart illustrating the operation in the case of controlin combination of charging, avoiding obstacles, working, and returningto the base portion.

The CPU core 40 receives the voltage of the power source portion 16, andjudges whether the voltage is higher than the predetermined referencevoltage VL or not (S131). If the voltage of the power source portion 16is lower than the predetermined reference voltage VL, the CPU core 40brings the micro robot into a charging operation (S132). This chargingoperation is the same as that in the above-mentioned respectiveembodiments. If the voltage of the power source portion 16 is higherthan the predetermined reference voltage VL, the CPU core 40 moves themicro robot (S133), and judges whether there is an obstacle or not(S134). Detecting an obstacle is performed by detecting with a sensorattached for detecting an obstacle, or by detecting the state in which astepping motor is not rotating. The detection in the latter is performedas follows. After a driving pulse is supplied to an exciting coil of astepping motor, an induced voltage becomes large if the stepping motoris rotating while the induced voltage becomes small if the steppingmotor is not rotating, so that the judgment can be performed bydetecting the degree of the induced voltage.

If it is proved that there is an obstacle (S134), the CPU core 40 bringsthe micro robot into an avoiding operation. Such an avoiding operationis performed through controls such as stopping, retreating, and so on.If it is proved that there is not any obstacle, the CPU core 40 bringsthe micro robot into a desired work (advancing and so on) (S136). Next,the CPU core 40 judges whether there is a base-position returninginstruction or not (S137), repeats the above-mentioned processing ifthere is not a base-position returning instruction, and returns themicro robot to the base position if there is a base-position returninginstruction (S138). Although work is continued till a base-positionreturning instruction is given from the outside in this embodiment, themicro robot may return to the base position automatically if work isfinished. Returning to the base position is performed in the same manneras moving to the charging stand.

I claim:
 1. A micro robot comprising:at least two sensors havingrespective detection regions partly overlapping each other; at least onepair of driving means, being driven independently of each other andhaving driven points separated from each other, each driven pointdefining a vertical axis extending therefrom in a directionperpendicular to a direction of movement; a control portion which iscomposed in a form of a thin plate, for controlling said driving meanson the basis of outputs of said sensors; a chargeable power sourceportion for supplying a power source voltage to said sensors, saiddriving means and said control portion; and wherein said control portionand said power source portion being arranged in parallel between saidpair of driving means, said driving means including an electromagneticstepping motor, said electromagnetic stepping motor comprising; amagnetic rotor, an exciting coil winding wound on a magnetic core, atabular stator having a circular hole to house said magnetic rotor, apair of recesses, each being smaller than said magnetic rotor openinginto the inside wall of said circular hole at diametrically opposedsites about the center of said circular hole and at a biased angle froma direction of a magnetic flux excited in said circular hole, and a pairof concave portions disposed outside said circular hole; said excitingcoil winding being arranged between both ends of said tabular stator,said micro robot further having a center of gravity positioned inapproximate alignment with a plane including the vertical axis of saiddriven points of said pair of driving means and below the highest heightamong the height of said driving means, said control portion and saidpower source portion.
 2. A micro robot according to claim 1, whereinsaid micro robot is supported by three points including said two drivenpoints which are driven relative to a running ground by said pair ofdriving means, and one sliding point which slidably contacts with saidrunning ground.
 3. A micro robot according to claim 2, wherein a linesegment connecting said two driven points interlinks with the directionof gravity of said micro robot at its center of gravity depending oninclination of said running ground, and the position of said slidingpoint varies between the front and back of the interlinkage.
 4. A microrobot according to claim 1, further comprising a flexible protrusionwhich projects from a body and which is conductive with said powersource portion.
 5. A micro robot according to claim 1, wherein each ofsaid driving means includes a motor constituted by a stepping motor. 6.A micro robot according to claim 1, wherein said control portion carriesout accelerating control on said driving means at the time of startingdriving of said driving means, and wherein said control portion makesthe driving condition of one of said driving means coincide with that ofthe other driving means when the driving of said one driving means isstarted while said other driving means is being driven.
 7. A micro robotaccording to claim 6, further comprising an obstacle sensor fordetecting an obstacle so that when said obstacle sensor detects anobstacle said control portion reversely drives at least one of saiddriving means for a predetermined period of time and then returns saidat least one driving means to its normal operation.
 8. A micro robotaccording to claim 1, wherein said control portion detects presence orabsence of rotation of a motor included in each of said driving means onthe basis of an induced voltage in a winding of said motor.
 9. A microrobot according to claim 1, wherein said control portion drives saiddriving means while accelerating, and wherein said control portionperforms driving with driving pulses the width of which is widened atthe time of starting while narrowed at the time of high speed.
 10. Amicro robot according to claim 1, wherein said control portion makes therespective timings of supplying driving pulses to said driving meanscoincident with other.
 11. A micro robot comprising:at least twodirection control sensors having respective detection regions partlyoverlapping each other; at least one pair of driving means being drivenindependently of each other and having driven points separated from eachother, each driven point defining a vertical axis extending therefrom ina direction perpendicular to a direction of movement; a work controlsensor which receives a work instruction contactlessly from an operationside; a work driving means; a control portion for controlling saiddriving means on the basis of outputs of said direction control sensorsand for controlling said work driving means on the basis of an output ofsaid work control sensor; and a chargeable power source portion, whichis composed in a form of a thin plate, for supplying a power sourcevoltage to said direction control sensors, said driving means, said workcontrol sensor, said work driving means, and said control portion;wherein said control portion and said power source portion beingarranged in parallel between said pair of driving means, said drivingmeans including an electromagnetic stepping motor, said electromagneticstepping motor comprising; a magnetic rotor, an exciting coil windingwound on a magnetic core, a tabular stator having a circular holehousing said magnetic rotor, a pair of recesses, each being smaller thansaid magnetic rotor opening into the inside wall of said circular holeat diametrically opposed sites about the center of said circular holeand at a biased angle from a direction of a magnetic flux excited insaid circular hole, and a pair of concave portions disposed outside saidcircular hole; said exciting coil winding being arranged between bothends of said tabular stator, said micro robot further having a center ofgravity positioned in approximate alignment with a plane including thevertical axis of said driven points of said pair of driving means andbelow the highest height among the height of said driving means, saidcontrol portion and said power source portion.